Mr. Howard Brown Vice President of Production & Engineering Triangle Brick Company 6523 NC Highway 55 Durham, North Carolina 27713-9413

Dear Mr. Brown:

Thank you for your efforts in coordinati ng the July 29, 2008, site visit by U. S. Environmental Protection Agency (EPA) and RTI personnel to the Triangle Brick facility in Merry Oaks, North Carolina. We appreciate th e time that you and other representatives at Triangle Brick set aside for discussing and showing your manufacturing process.

Enclosed is a draft of the tr ip report (Enclosure 1) that has been prepared based on the information obtained during our site visit. We would appreciate your reviewing the report for any errors or omissions. You may return the en closed copy of the report with your written comments. Since this report will eventually beco me a part of the public record, we want to portray your operations as accurately as possible. A copy of the final version of the report incorporating your comments will be sent to you for your records.

The custody receipt for the trip report is also enclosed (Enclosure 2) . Please sign and date the form to acknowledge rece ipt of the report and return a copy of the form to: Mr. Roberto Morales; U.S. Environmental Prot ection Agency; Office of Air Quality Planning and Standards; IO/PRRMS (MD-C404-02); 109 T.W. Alexander Drive; Research Triangle Park,

North Carolina 27711.

If you believe that disclosure of any speci fic information contained in the trip report

would reveal trade secrets or other confidential in formation, you should clearly identify the specific information. Please do not label the enti re report as “confidential” if only certain portions consist of trade secret information. If the EPA determines that there is a need to disclose such information, we will need, at that time, the following to support your claim:

1. Measures taken by Triangle Brick to guard against undesire d disclosure of the specific information to others;

2. The extent to which the specific informa tion has been disclosed to others and the precautions taken in connection therewith;3. Pertinent confidentiality determinations, if any, by other Federal agencies (furnish a copy of any such determination, or re ference to it, if available); and

4. Whether Triangle Brick asserts that disclo sure of the specific information would be likely to result in substantial harmful effects on Triangle Bricks’ competitive position, and, if so, what those harmful effects would be, why they should be viewed as substantial, and an explanation of the causal relationship between disclosure and such harmful effects.

Any specific information subsequently determ ined to constitute a trade secret will be protected under 18 U.S.C. 1905. If no claim of confidentiality accompanies the information when it is received by EPA, it may be made av ailable to the public by EPA without further notice (40 CFR Part 2.203, September 1, 1976). Any specific information subsequently

determined to constitute a trade secret will be protected under 18 U.S.C. 1905. However, all emissions data will be available to the public. A clarification of the information EPA considers to

be emissions data is co ntained in Enclosure 3.

We respectfully request that you submit your review comments on the trip report by October 15, 2008. If you concur with the inform ation contained in the report, we would appreciate a letter to that eff ect. In addition, please indicate in your letter the specific parts of the report, if any, that Triangle Bric k considers to be conf idential. If we do not receive a response by October 15, 2008, the report will be consid ered nonconfidential and accurate.

Thank you for your cooperation. The informa tion supplied by Triangle Brick will be most helpful in our study. If you have any questions, pl ease call Mr. Jeff Telander of my staff at (919) 541-5427 or Mr. Rick Marinshaw of RTI at (919) 316-3735.

Sincerely,

Steve Fruh Group Leader Metals and Minerals Group Office of Air Quality Planning and Standards

3 EnclosuresEnclosure 3